This program grant is concerned with biochemical and biological aspects of perinatal life. It emphasizes two main biological areas: 1) Cellular and organ behavior, 2) Organismal growth and development. The primary objective is to study the effect of various environmental stimuli on different phases of intrauterine and extrauterine growth and to examine the ability of the organism to adapt to these influences. We have proposed specific model systems for investigation. Intestine will be studied with emphasis on (a) The brush border membrane, (b) Disaccharidases and (c) Selected clinical cases of intractable infant diarrhea. Liver studies will include (a) Neonatal jaundice and (b) Acquired defects of urea biosynthesis. Functional development of the pancreas will be examined in relation to synthesis of digestive enzymes and diet. Oxygen transport will be studied in relation to hemoglobin AIc in diabetic mothers and their infants, and in infants of low birth weight. Developmental aspects of hemoglobin synthesis will be investigated using erythroblasts from avian embryonic liver as the experimental model system. Additional studies will focus on selected hereditary disorders of erythropoiesis leading to unexplained hemolytic anemia and polycythemia in the neonatal period.